Age at first reproduction in male fallow deer: age-specific versus dominance-specific behaviors

The argument that an optimal age at first reproduction evolveswhere the benefits of reproduction outweigh the costs impliesthat where conditions change, age at first reproduction shouldalso change. We studied six captive populations of fallow deer(Dama dama) that differed in the age structure of males, maledensity, and sex ratio. We examined responses of males to changesin competition by simulating the presence of additional malesby providing visual, olfactory, and auditory stimuli. Our resultssuggest that dominance rank was the most important factor indetermining the level of reproductive behaviors exhibited. Theparticipation in reproduction increased with dominance status,and this association held for males that are usually sociallyimmature (3-5 years old). Hence, age apart from dominance wasrelatively unimportant in affecting the reproductive behavior.Male density was positively correlated with the time spent walkingand standing The female-to-male ratio was positively relatedto male-female interactions, but negatively related to male-maleinteractions. In response to the simulations, males older than3 years increased the rate of reproductive behaviors, but youngermales did not change or decreased the rate. We conclude thatonly males up to 3 years of age refrained from reproductionunder competition by mature males. However, past 3 years ofage, investment in reproduction is a function of dominance ratherthan a function bf age. This implies that 4- and 5-year-oldmales do not seems to defer reproduction until socially maturebut that their participation is a correlate of the achievabledominance rank.     

Genetic and behavioural estimates of reproductive skew in male fallow deer

Populations of fallow deer, in general, have low genetic diversity. Nevertheless, we screened 39 microsatellite loci and identified 20 that were polymorphic and suitable to determine paternity of fallow deer. To date, paternity has been studied for 87, 110 and 152 fallow deer fawns born between 2000 and 2002. Our results confirm the existence of a strong polygynous mating system in our population and confirm that the number of copulations performed by males is globally a good estimator of their reproductive success: males which performed the largest proportion of matings fathered the largest proportion of fawns. Nevertheless, we report some differences between the two measurements of the males' reproductive success: measures of copulatory success underestimated the variance of the males' reproductive success. On average, males whose copulatory score exceeded their paternity had mated with a higher proportion of younger females. Young females may be more likely to lose the conceptus, or their offspring may suffer high postnatal mortality.     

Genetic variability in fallow deer, Dama dama L

Summary. Twelve blood proteins and enzymes were tested for polymorphism in a herd of fallow deer, Dama dama L., bred for meat production in Western Germany, to investigate the genetic constitution of the population. Although an enzyme polymorphism was detected (Catalase) for the first time in this species, electrophoretic variation is very low in comparison to other large ungulates. Possible explanations for this finding, such as recent inbreeding and a past genetic bottleneck, are given. The relationship between low genetic variation in biochemical marker systems and fitness is discussed.     

Genes, copying, and female mate choice: shifting thresholds

Recent experimental work on guppies (Poecilia reticulata) hasexamined the strength of genetic and cultural (copying) factorsin determining female mate choice. Using females from a populationwith a heritable preference for the amount of orange body colorpossessed by males, prior work discovered that a threshold differencein orange color among males existed below which females wouldchoose a less orange male if they observed another female choosethat male, but above which they consistently preferred the moreorange of the males, regardless of whether they viewed anotherfemale prefer the less orange male. I tested whether this thresholdcan be shifted by increasing the amount of mate-copying informationavailable to a female. I demonstrate that when a female hasthe opportunity to see two different model females independentlyprefer the less orange of two males or a single female neara drab male for a longer period of time (twice as long as inprior work), the observer female prefers this drab male evenwhen males dramatically differ in orange coloration.     

Nonindependent mating in a coral reef damselfish: evidence of mate choice copying in the wild

Theoretical and experimental studies have shown that mate choicecopying is a viable mating strategy under certain conditions.Copying experiments in fish have been conducted primarily inthe laboratory, except for one study conducted in the fieldunder artificial conditions. We investigated whether in a wildpopulation of the coral reef whitebelly damselfish (Amblyglyphidodonleucogaster) females copy the choice of other females. Femalespreferentially spawn with males that have recently mated. Todetermine if the presence of new eggs in the nest was the reasonfemales chose mates or whether females were mate choice copying,we conducted egg-switching experiments. Eggs from males thatrecently mated were donated to males that had no eggs. If femalesare mate choice copying, then donor males with no eggs in thenest should continue to receive additional eggs. If femalesare using the presence of new eggs as the criterion for matechoice, then foster males with new eggs should receive additionaleggs. We found that donor males received new eggs significantlymore often than expected. More females mated with donor malesthan foster males. Furthermore, females preferentially choseto mate with males whom they had seen mating with another female.Females appear to remember the mate choice of other femalesand choose to mate with those same males even after 1 day. Theseresults suggest that females may be copying the mating decisionof other females rather than choosing males based on the presenceof new eggs in the nest.     

游客密度对动物园中黇鹿行为的影响

2006年9月20日-10月10日,以江苏省扬州市茱萸湾公园半散放鲇鹿为研究对象,采用目标动物取样法和全事件记录法,研究了不同游客密度条件下黇鹿日行为时间分配.并探讨了游客密度对鲇鹿日活动的影响.结果表明:在游客高峰期与低峰期,雄性取食、观望行为,雌性观望以及幼鹿取食、观望和修饰行为之间均存在显著差异(P＜0.05).在游客低峰期,雄性与雌性取食、反刍、卧息行为,雄性与幼鹿观望、其它行为,雌性与幼鹿取食、卧息、观望均存在极显著差异(P＜0.01);在游客高峰期,雄性与雌性取食、卧息,雌性与幼鹿取食、卧息、观望及移动行为均差异极显著(P＜0.01),雄性和幼鹿观望行为差异显著(P＜0.05).不同游客密度条件下游客活动对鲇鹿的取食、观望具有显著影响,当游客密度达到6人·min-1以上时,雄性观望行为显著增加,当达到16人·min-1以上时,雄性取食行为差异极显著(P＜0.01),此时雌性和幼鹿观望行为差异亦达到极显著水平(P＜0·01).因此,在旅游管理中,应将游客密度限制在16人·min-1以下,以减少对鲇鹿日活动影响.     

Early growth in male and female fallow deer fawns

In this paper we present data from a long-term study on earlygrowth and related variables in fallow deer fawns living inlarge enclosures. Pre-winter body mass was constantly higherand more strongly correlated to subadult body mass in malesthan in females. To find out the mechanism for this higher pre-wintermass in males, we analyzed the variation in pre-winter massin relation to sex, year, mother's body mass, age and parityof mother, birth date, birth mass, growth rate, suckling behavior,and other behaviors. Birth mass was higher for male fawns, andgestation length, birth date, and weaning date did not differbetween the sexes. Consequently, both pre- and postnatal growthwere faster in males than in females. No behavioral differenceswere found between the sexes that could explain the differencein postnatal growth. Pre-winter mass was positively relatedto mother's body mass. Heavy mothers gave birth earlier andto larger offspring who grew at a higher rate, independent ofoffspring sex. However, male fawns born to primiparous mothershad relatively lower growth than male fawns born to multiparousmothers. This was not the case for female fawns. Suckling timeafter the first 2 weeks was positively related to mother's bodymass and growth of offspring. However, no measurements of sucklingbehavior differed between male and female fawns. Our results,except for the effect of parity on male and female growth, indicatethat selection has not acted on mothers to promote faster earlygrowth in males.     

Postcopulatory vocalizations of fallow bucks: who is listening?

Fallow bucks (Dama dama) produce a postcopulatory vocalization (PCV), consisting of an increase in the short-term groaningrate during the first min after mating. In this article, weconsider two main hypotheses to assess the possible functionof the postcopulatory vocalization. First, the PCV could bedirected at females, and used to advertise the current fertility status of the male. Second, the PCV could be directed at males,and used to transmit an intrasexual threat signal. We foundthat during days when a male gained many matings, his PCVsdid not decline, and males with larger intervals between matingsdid not produce higher PCVs. Lower PCVs were not associated with infertile matings, and for females that mated twice withinthe same estrus, the PCVs of their first matings were not lowerthan other PCVs. In addition, higher PCVs were not associatedwith shorter intervals to a male's next mating. Thus, therewas no evidence to suggest that the PCV was involved in transmittinga signal of fertility assurance, either to females that had mated, or to those that were about to mate. We found that PCVsdeclined as males reached the end of their mating success,therefore suggesting that PCVs are more likely to be involvedin transmitting an intrasexual threat signal related to currentcondition and/or motivation. We suggest that this signal is probably involved in mate guarding.     

Biochemical and histological study of the ossification in the early developing pedicle of the fallow deer (Dama dama)

To date, no histochemical data exist concerning the process of ossification of developing pedicles in deer. Four different zones of the growing pedicle (subcutaneous tissue; fibrous layer of the periosteum; cambial layer of the periosteum; women bone of the primary spongiosa) were analysed in direct correlation to their histological appearance. The level of extractable specific alkaline phosphatase in the preosseous zones of the pedicle was 4-fold higher than levels in the epiphyseal growth plate previously reported. These results reflect that rapid bone formation takes place in the growing pedicle. Highest buffer-extractable alkaline phosphatase activity was found in the cambial layer directly in front of the mineralization area of the pedicle-bone, connected with maximal values for organically bound phosphate and inorganic phosphate. Moreover, the values for buffer-extractable alkaline phosphatase, organically bound phosphate and inorganic phosphate decreased with increasing mineralization in the zone of the primary spongiosa. The present histological and biochemical findings on the process of ossification in the pedicle show similarities to typical endochondral ossification. The process of pedicle growth may serve as a new and important system for chondrogenic and osteogenic studies, including a better understanding of antler development.     

Conception rates following intrauterine insemination of European (Dama dama dama) fallow deer does with fresh or frozen-thawed Mesopotamian (Dama dama mesopotamica) fallow deer spermatoza

A total of 121 European fallow deer does, being either parous ( n = 15) or nulliparous ( n = 106), were treated with intravaginal progesterone impregnated controlled internal drug release (CIDR) devices for 14 days. The does were divided into three treatment groups and inseminated in utero by laparoscopy, at approximately 65 hours after CIDR device removal, with 25 × 10⁶ fresh Mesopotamian ( n = 40), 25–35 × 10⁶ frozen-thawed Mesopotamian ( n = 41) or 30–32.5 × 10⁶ frozen-thawed European ( n = 40) fallow deer spermatozoa. The semen used had been collected, from two Mesopotamian and two European fallow deer bucks, by electroejaculation under general anaesthesia. Pregnancy was diagnosed by rectal ultrasonogrdphy on Day 50 after insemination.
There were no apparent differences in the quality of ejaculates between the two subspecies of fallow deer. The volume of semen and the total number of spermatozoa ranged between 0.6–1.2 ml and 2.11–4.95 × 10⁹ per ml of semen, respectively. Evaluation of frozen-thawed spermatozoa revealed post-thaw motility rates between 50–70%. The overall conception rate was 65.3%. A higher conception rate was observed following insemination with European than Mesopotamian frozen-thawed spermatozoa (75% vs. 53.7%, respectively, P < 0.05). Insemination with fresh Mesopotamian spermatozoa increased the conception rate to a level not significantly different from that observed following insemination with European frozen-thawed spermatozoa (67.5% vs. 75%, for fresh Mesopotamian and frozen-thawed European semen, respectively).     

Functional directional asymmetry in fallow deer (Dama dama) antlers

The right antlers of fallow deer are significantly more developed than the left antlers with respect to the lengths of the beam, trez tine and palm, as well as antler weight and number of points. The cross-section at the base is also more elliptical in the right antler. The size difference is correlated with the more intense use of right antlers in fighting, and with the greater breadth of the areas of insertion of the neck muscles in the skull's nuchal region.     

Cardiac rhabdomyoma in a juvenile fallow deer (Dama dama)

A cardiac rhabdomyoma is described in a 6-wk-old captive fallow deer (Dama dama) that died suddenly without previous clinical signs. The tumor was characterized by multiple nodules composed of large atypical vacuolated myoblastic cells. As previously reported in humans and other animal species, there is compelling evidence that the cardiac rhabdomyoma is a congenital developmental anomaly rather than a true neoplasm. To our knowledge, this is the first report of a cardiac tumor and a rhabdomyoma in a cervid species.     

Breeding behavior of female white‐tailed deer relative to conception: Evidence for female mate choice

Female white‐tailed deer (Odocoileus virginianus) are thought to choose between two behavioral strategies to maximize the quality of potential mates: sit and wait, characterized by concentrating activity within a restricted area, and excursive behavior, characterized by increased activity and excursions outside the home range. As movement patterns may influence conception, our goal was to examine the patterns of female white‐tailed deer movements to evaluate which breeding strategy was employed. We equipped 36 female white‐tailed deer with GPS collars from August 2013 to December 2015. We found that movement rate and probability of activity were greatest near the peak of the breeding season, and we observed increases in both metrics during the 40 days prior to estimated conception. Peak size of home range and core area occurred in the days surrounding conception. We found that 11 deer performed an excursion, ranging from 43 days before until 36 days after conception, with the peak probability of being outside of an individual home range occurring 1 day prior to conception. Our results suggest that female white‐tailed deer may attempt to maximize the quality of their mates by advertising availability for breeding through excursive behaviors just prior to entering estrus.